RELAXANT ACTION OF HISTAMINE ON RABBIT TRACHEA - POSSIBLE EXISTENCE OF 3RD HISTAMINE RECEPTOR SUBTYPE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 23  (2) , 211-221
Abstract
The carbachol contracted rabbit treachea relaxes to isoproterenol, PG[prostaglandin]E1, PGE2, histamine and bradykinin. Histamine-induced relaxations were resistant to mepyramine (an H1-antagonist), burimamide, cimetidine, metiamide (H2-antagonists), propranolol (a .beta.-adrenoceptor blocker), indomethacin (a potent inhibitor of PG synthesis), trasylol (an inhibitor of kallikreins), aminophylline (a purinergic receptor blocker) and dibenzyline (a "D"-tryptamine receptor antagonist). The evidence achieved with these pharmacological agents appears to suggest that the chemical mediator responsible for the relaxant response to histamine is unlikely to be: catecholamines, PG, 5-HT [5-hydroxytryptamine], adenosine or ATP or kinins. The existence of H2-(iso or H3) histamine receptor subtype in rabbit trachea is postulated.